In recent years, a commodity management by POS system (point of sales system) has been executed very actively. The optical device for reading information like a bar code reader has been used for the POS system.
Namely, such data processing as an inventory management has been executed by displaying the information about the commodities (a kind of commodities and cost of commodities and so on) in a bar code as an information medium, reading the bar code with the bar code reader, and processing the information in a host computer.
Recently, also in a physical distribution field, such work as an assortment is often executed by displaying a bar code as an information medium on the commodity and the box, and reading the bar code with a bar code reader.
Some of the devices for reading information like the bar code reader are provided with a device for scanning light. Generally, a method in which the light scanning is executed by revolving a polygon mirror and a galvano mirror mechanically has been adopted for the traditional device for scanning light.
Accordingly, the device for scanning light provided with mechanically movable parts has caused some problems that a controllability is deteriorated and a response delay occurs and so on, and has caused some deficiencies that the optical axis is slipped off by the mechanical vibration and so on.
On the other hand, various methods have been suggested for a display device which displays a stereoscopic picture up to the present. One example is a binocular method represented by a spectacle method in which a cubic effect is obtained by binocular convergence and binocular parallax, letting the left and right eyes look at the different pictures. Besides, a lenticular method of multiple-lens method exists as an extension of the binocular method. A principle of the stereoscopic vision in the lenticular method is the same as the binocular method.
Only unnatural stereoscopic pictures can be seen in such method for stereoscopic display, since no difference (kinetic parallax) occurs in the stereoscopic pictures even if the observer moves his head from left to right.
Holographic stereogram is cited as a method to solve these problems. In holographic stereogram, the natural cubic effect can be obtained even if the observer moves his head from left to right, since the two-dimensional pictures including the parallax are registered in a segment hologram of vertically slender slit form, and a large number of these pictures are arranged horizontally. Besides, holographic stereogram including vertical parallax also exists.
First of all, an object will be photographed moving the camera position vertically if the holographic stereogram which has a vertical parallax is given as an example.
Then, a laser light is applied to the film to which the object was photographed, an object light is beamed by projecting the film against the diffusion board with lens, a slit of a slit board is arranged in front of the hologram dry plate corresponding to the projection position, and the interference fringes are exposure-registered by interfering with the reference light.
Further, a method for preparing an imaged hologram also exists. Namely, the imaged holographic diagram (image type holographic stereogram ) is prepared by applying the laser light to the hologram which was prepared as mentioned above so that the light will be converged into the replay light source indicated as a virtual image, installing another hologram dry board in a display position of the image according to the object light wave-front converted by the hologram and exposing the dry board in irradiation of the reference light.
The image type holographic stereogram is capable of displaying the stereoscopic image by applying the replay light to it, reviewing it from the visual region in the wave-front conversion.
It is desirable that the stereoscopic image exists near the holograph surface so as to reduce the fatigue of the observer""s eyes, when the stereoscopic display is executed. In the above-mentioned holographic stereogram, it is necessary to image the picture photographed by camera, since the stereoscopic images are replayed so that they will be piled up on the hologram surface.
On the other hand, in the image type holographic stereogram, the hologram surface and the stereoscopic image can be piled up without converting the pictures, since the two-dimensional pictures are on the hologram. Besides, there are some advantages that the image surface will be on the hologram surface and the chromatic aberration will not occur, even if the wavelength of the light which refers to the holograph changes and so on. Accordingly, it can be said that the stereoscopic display by the image type holographic stereogram is easier to see.
Besides, an Audio Optical Deflecting system (AOD) consisting of tellurium dioxide crystal is used as another device for stereoscopic display, and a display device provided with a galvano mirror scanner, polygon mirror and a lens is also known. In the device, the interference fringes formed on the hologram dry board are calculated by the computer from the three-dimensional data of the object which is displayed as a hologram. The data of the interference fringes are written into a frame buffer of the computer, and a picture signal and a synchronization signal are transmitted to the display unit.
In the display unit, the picture signal and the synchronization signal are separated into an optical scanning partial synchronization signal and a hologram signal which activates the audio optical deflecting system from the compound hologram signal for CRT display of the computer. At this moment, the hologram signal should be intermingled with the 100 MHz carrier wave, since the frequency band necessary for activating the audio optical deflecting system is from 50 MHz to 100 MHz. The refractive index variation which is modulated resiliently occurs, when its transmission signal is converted into an ultrasonic wave by the ultrasonic transducer of the audio optical deflecting system (AOD) and the crystal within the audio optical deflecting system (AOD)is transmitted by the ultrasonic wave. The diffracted light can be obtained if the laser light is injected into there. Although a hologram is formed within the audio optical deflecting system (AOD) by these actions, the hologram should be stopped by synchronizing the polygon mirror in sound speed and revolving it, since the hologram is moving in sound speed ( slow shear wave of the tellurium dioxide crystal, 617 per second). At this moment, the polygon mirror is also used for scanning the small element holograms horizontally at the same time. The horizontal line hologram formed like this should be scanned vertically by the galvano mirror scanner to replay the three-dimensional image. Accordingly, the three-dimensional image can be seen floating in the space in front of outgoing radiation lens installed behind the polygon mirror.
By the way, the high control accuracy can not be desired and the mechanical control delay can not be avoided, if the device for stereoscopic display owns such mechanically movable parts as the polygon mirror and the galvano mirror scanner. Besides, such problems as the slippage of the light axle due to the occurrence of noises by the mechanical resonance might result in obtaining a stereoscopic picture of poor quality. Further, such maintenance as a mechanical adjustment can not be easily executed.
For this reason, the electronic display of the hologram using, for instance, the spatial light modulation element in which the liquid crystal is used as a deflecting part was also considered. However, although the picture element pitch of the liquid crystal display must be around 1 xcexcm so as to obtain an enough deflection angle (around 30 degrees) when the liquid crystal is used as the deflecting part, it was impossible to do so in reality. Besides, in traditional LCD (Liquid Crystal Display), the spatial frequency of only the integral number twofold of the picture element can be represented, but the deflection of the non-stage using the LCD was inexecutable.
By the way, generally, it is necessary to obtain a phase distribution of the light by the calculation of the computer from the three-dimensional object to be displayed, and it is necessary to calculate the phase distribution from the two-dimensional picture in connection with the image type holographic stereogram, in order to display the hologram electronically by using the spatial light modulation element in which the liquid crystal is used.
The calculation of the phase distribution divides the hologram surface into the microscopic hologram regions, calculates the phase distribution per inaccurate region from the position coordinates and the intensity of all sample points of the object and executes the calculation in connection with all of the microscopic hologram regions. For this reason, the calculation volume is increased considerably also in the image type holographic stereogram in which the phase calculation is executed for the two-dimensional pictures.
Besides, it is necessary to calculate a phase distribution and the load of the computer calculation becomes heavy, whenever the contents of the two-dimensional pictures to be displayed are changed, so the improvement of these points has been desired.
Accordingly, it is desirable that the stereoscopic display can be executed for the image type holographic stereogram without calculating the phase distribution even if the two-dimensional pictures are changed.
The object of the present invention is to realize an apparatus for deflecting light which does not have a mechanically movable part, and in which the deflection of the non-stage is executable and the control is easily executed.
The object of the present invention is to realize a device for scanning light which does not have a mechanically movable part, and in which the light scanning can be executed continuously, the control is easily executed and the miniaturization is executable.
The object of the present invention is to realize a device for reading information whose controllability is good and reliability is high.
The object of the present invention is to realize a device for stereoscopic display provided with a beam deflection means which does not have a mechanically movable part.
Another object of the present invention is to realize a device for stereoscopic display provided with an apparatus for deflecting light which owns an enough deflecting angle without a minute processing of the picture element, and in which the deflection of the non-stage is executable.
Another object of the present invention is to realize a device for stereoscopic display which executes a stereoscopic display without calculating a phase distribution. The following means were adopted for the present invention so as to attain at least one of the above-mentioned objects.
An apparatus for deflecting light of the present invention comprises: (a) at least one pair of transference electrodes arranged facing one another; (b) a drive circuit which applies a voltage among the transference electrodes; and (c) a liquid crystal which is inserted among the transference electrodes, and whose parallel stripes which function as a diffraction grating when the voltage is applied among the transference electrodes are produced at a pitch corresponding to the applied voltage.
In the apparatus for deflecting light of the present invention, the liquid crystal whose anisotropy of a permittivity is less than 0 is ideal. Hereupon, the anisotropy of the permittivity means a value in which the permittivity of minor axis direction is subtracted from the permittivity of the major axis direction in the liquid crystal. It is also referred to as a permittivity difference.
Besides, it is understood that the pitch of the parallel stripes which occurs in the liquid crystal becomes narrower and the angle of diffraction gets bigger in proportion to the enlargement of the applied voltage. In the apparatus for deflecting light of the present invention, it is also possible to apply a voltage whose voltage value changes temporally among the transference electrodes by the drive circuit. By these actions, the angle of diffraction can be changed temporally, and it will be possible to control the angle of diffraction electrically.
Both dc voltage and alternating voltage can be used as the applied voltage.
A device for scanning light of the present invention comprises: (a) an apparatus for deflecting light whose liquid crystal is inserted among the transference electrodes arranged facing one another, and whose parallel stripes which function as a diffraction grating when the voltage is applied to the transference electrodes are produced at a pitch corresponding to the applied voltage in the liquid crystal; (b) a drive circuit which applies a voltage whose voltage value changes temporally among the transference electrodes of the apparatus for deflecting light; and (c) a light source which beams the light which will be injected into the apparatus for deflecting light.
The light can be scanned by using the diffracted light which is an outgoing light of the apparatus for deflecting light as a scanning light, since the angle of diffraction will change temporally if the size of the applied voltage of the apparatus for deflecting light is changed temporally.
In the device for scanning light of the present invention, an optical element for converging light can be installed on the incident light side or the outgoing light side of the apparatus for deflecting light. The convex lens can be exemplified as the optical element for converging light.
The optical element for converging light can bring the image formation point of the light closer to the apparatus for deflecting light, compared with the case that the apparatus for deflecting light does not have an optical element for converging light, when the light beamed from the light source is a focusing ray. The optical element for converging light can converge the light beamed from the light source and make it form as a image, when the light beamed from the light source is a divergent ray or a parallel ray.
In the device for scanning light of the present invention, an incident light angle of the incident light against the apparatus for deflecting light can be set almost equally to a Bragg angle of the diffracted light used for the scanning light. By these actions, the diffraction efficiency can be maximized, and the intensity of the diffracted light used as a scanning light can be bigger than the intensity of other diffracted light.
In the device for scanning light of the present invention, an optical element which enlarges a deflection angle of the scanning light substantially can be installed on the outgoing light side of the apparatus for deflecting light. The scanning width of the scanning light can be enlarged and the device for scanning light can be miniaturized, if the deflection angle of the scanning light can be enlarged.
A convex lens, a concave lens, a convex mirror and a hologram and so on can be exemplified as the optical element which enlarges the deflection angle of the scanning light substantially.
In the device for scanning light of the present invention, an aperture can be installed between the light source and the apparatus for deflecting light, Besides, the beam diameter can be reduced and the wished-for beam shape can be set by the aperture.
Especially, the reflected light intensity contrast of the reflected light which reflects in the information medium can be improved, when the device for scanning light provided with the aperture is included in the device for reading information.
The device for scanning light of the present invention can be provided with a variable mechanism which makes a clearance along an optical axis direction from the light source to the optical element for converging light variable. Namely, either the light source or the optical element for converging light is fixed so that the other side will be moved by the variable mechanism along the optical axis direction. Either the light source or the optical element for converging light can be moved by the variable mechanism. By these actions, the position of the image formation point of the scanning light can be made variable.
The device for scanning light of the present invention can be provided with: (a) a half mirror which reflects an outgoing light of the optical element for converging light towards the direction alienated from the apparatus for deflecting light; (b) a second optical element for converging light which converges the reflected light beamed from the half mirror; (c) a reflecting member which reflects the outgoing light of the second optical element for converging light and lets the reflected light permeate through the second optical element for converging light and the half mirror to inject it into the apparatus for deflecting light; and (d) a variable mechanism which changes a clearance along an optical axis direction from the second optical element for converging light to the reflecting member.
In this case, either the second optical element for converging light or the reflecting member is fixed so that the other side will be moved by the variable mechanism along the optical axis direction. Either the second optical element for converging light or the reflecting member can be moved by the variable mechanism.
In the device for scanning light of the present invention, a plurality of apparatuses for deflecting light can be provided, the apparatuses for deflecting light can be arranged in layers so that the parallel stripes which occurs in each apparatus for deflecting light will be crossed one another, and a voltage can be applied to each of the apparatuses for deflecting light mutually by the drive circuit.
By these actions, the scanning light can be scanned to a plurality of directions changing the scanning directions in order. Hereupon, it is not always necessary to make the apparatuses for deflecting light contact one another so as to pile up the apparatuses for deflecting light, and a crevice can be existed among the apparatuses for deflecting light. The crossed axes angle is not limited in particular.
In the device for scanning light of the present invention, a polarizer can be installed on the outgoing light side of the apparatus for deflecting light. The polarizer shuts down almost all of the unnecessary diffracted lights except the scanning light. As a result, the device for scanning light will be hardly influenced by any diffracted lights except the scanning light, the performance of the device for scanning light can be improved, and the simplification of the device and the extension of the degree-of-freedom of the design can be attained.
In the device for scanning light of the present invention, the polarizers can be installed on the outgoing light side of the apparatus for deflecting light, and the polarizers can be arranged so that the polarizing direction of the polarizer will be almost perpendicular against the polarizing direction of the incident light to the apparatus for deflecting light.
The laser light of the linearly polarized light of S polarization or P polarization is desirable as a light beamed from the light source. The polarizer can be arranged between the light source and the apparatus for deflecting light so that only the linearly polarized light component will be injected into the apparatus for deflecting light, when the light beamed from the light source is not the linearly polarized light. The device for scanning light of the present invention can be used for a device for scanning light included in a bar code reader and a laser printer and so on.
A device for reading information of the present invention comprises: (a) an apparatus for deflecting light whose liquid crystal is inserted among the transference electrodes arranged facing one another, and parallel stripes which function as a diffraction grating when the voltage is applied to the transference electrodes are produced at a pitch corresponding to the applied voltage; (b) a drive circuit which applies a voltage whose voltage value changes temporally among the transference electrodes of the apparatus for deflecting light; (c) a light source which beams the light which will be injected into the apparatus for deflecting light; and (d) an apparatus for detecting light which detects a reflected light when the scanning light diffracted by the apparatus for deflecting light is reflected in an information medium.
The scanning light beamed from the device for scanning light is irradiated to the information medium, and is reflected in the information medium, then its reflected light is injected into the device for detecting light. The light signal inputted into the device for detecting light is converted into an electric signal by appropriate means to be read.
In the device for reading information of the present invention, the bar code can be substituted for the information medium.
In the device for reading information of the present invention, shading means for cutting off a zero-order diffracted light of the device for deflecting light can be installed on the outgoing light side of the apparatus for deflecting light.
By these actions, the reflected light of the transmitted light can not be injected into the device for detecting light, since the transmitted light of the apparatus for deflecting light is cut off by the shading means. Accordingly, the reading accuracy will be improved.
A device for stereoscopic display of the present invention comprises: (a) two-dimensional-picture-display means for displaying two-dimensional pictures which vary in visual directions; and (b) beam deflection means for deflecting a light beamed from a picture element which organizes the pictures of the picture display means. The apparatus for deflecting light whose liquid crystal is inserted among the transference electrodes, and parallel stripes which function as a diffraction grating when a voltage is applied among the transference electrodes are produced at a pitch corresponding to the applied voltage is used for the beam deflection means.
In the device for stereoscopic display of the present invention, the photographed pictures are inputted from a plurality of visual directions. The inputted plural parallax pictures are displayed on the two-dimensional picture display means. Then, inputted pictures are deflected to the corresponding designated visual regions respectively. For instance, the picture inputted from the first visual direction is deflected to the virtual first aperture, the picture inputted from the second visual direction is deflected to the virtual second aperture and the picture inputted from n the visual direction is deflected to the virtual n the aperture. By these actions, the angle relation between the object and the camera when the picture is inputted will be same as the angle relation between the observer and the displayed picture when the picture is replayed, so the stereoscopic picture can be replayed.
Each of the parallax pictures in one time t=t1 should be rearranged in time series to display the two-dimensional pictures in order during xcex94t (for instance, xcex94t={fraction (1/30)} seconds) when an animation is replayed (the picture display of Scene 1). The parallax pictures in t=t1+xcex94t should be arranged in the time series similarly to execute the displays, after executing the displays on the basis of the number of visual points (the picture display of Scene 2). The animation should be displayed by repeating these actions.
In the device for stereoscopic display of the present invention, a device for stereoscopic picture display without mechanically movable parts can be realized, since the apparatus for deflecting light into which the liquid crystal is inserted is used as the beam deflection means.
The device for stereoscopic display of the present invention comprises: (a) a line division unit for dividing a picture photographed by a camera into a number of visual points; (b) a time series rearrangement unit for rearranging the two-dimensional pictures divided by the line division unit in the time series; (c) a two-dimensional picture display unit for replaying and controlling the two-dimensional pictures rearranged by the time series rearrangement unit in a time series order. The beam deflection means can deflect the two-dimensional pictures displayed by the two-dimensional picture display means to a virtual aperture corresponding to an camera visual point of the plural cameras.
In the device for stereoscopic display of the present invention, the pictures can be deflected to a horizontal direction by the beam deflection means.
In the device for stereoscopic display of the present invention, the pictures can be deflected to a vertical direction by the beam deflection means.
The device for stereoscopic display of the present invention can be provided with first beam deflection means for deflecting the pictures to the horizontal direction and second beam deflection means for deflecting the pictures to the vertical direction.
In the device for stereoscopic display of the present invention, the two-dimensional picture display means has a picture element for displaying the pictures, and the beam deflection means can be provided independently per picture element which organizes the pictures.
In the device for stereoscopic display of the present invention, the two-dimensional picture display means has a picture element for displaying the pictures and the beam deflection means can be provided extending over a plurality of picture elements which organize the pictures.
In the device for stereoscopic display of the present invention, the beam deflection means executes the deflection only to the horizontal direction, and light diffusion means for diffusing the light to the vertical direction can be provided.
In the device for stereoscopic display of the present invention, the beam deflection means is controlled by the deflection control unit and the deflection control unit can refer to a phase-distribution table in which a phase-distribution data are stored to determine a deflection angle of the beam deflection means. By these actions, it is not necessary to calculate the phase distribution whenever the picture is switched.
In the device for stereoscopic display of the present invention, a pair of polarizing plates which are arranged before and behind the beam deflection means and whose deflecting directions are crossed in an angle of 90 degrees xc2x110 can be-provided.
In the device for stereoscopic display of the present invention, an elimination time of the display screen can be prepared in the deflection control unit in which the beam deflection means is controlled before rewriting the screen, when the deflection is moved from one virtual aperture to the next virtual aperture by the beam deflection means, and the deflection can be stopped during the time.
In the device for stereoscopic display of the present invention, an elimination time of the display screen can be prepared in the deflection control unit in which the beam deflection means is controlled before rewriting the screen, when the deflection is moved from one visual aperture to the next virtual aperture by the beam deflection means, and the deflection can be stopped during the time and the intensity of the image display by the two-dimensional picture display means can be darkened at the same time.
The device for stereoscopic display of the present invention can be provided with a record/replay unit for recording and replaying a photographed picture.
A system for stereoscopic picture communication of the present invention comprises a transmission side that transmits a plurality of two-dimensional pictures which vary in visual directions through a communication network and a receiving side that receives the transmitted two-dimensional pictures, and displays them by the two-dimensional picture display means which displays the received two-dimensional pictures, and displays a stereoscopic picture in a remote location by deflecting the light beamed from the picture element which organizes the pictures of the picture display means corresponding to the different visual directions in the beam deflection means. An apparatus for deflecting light whose liquid crystal is inserted among the transference electrodes arranged facing one another, and parallel stripes which function as a diffraction grating when the voltage is applied among the transference electrodes are produced at a pitch corresponding to the applied voltage in the liquid crystal is used for the beam deflection means.